Pneumatic hammer.



No. 690,358. Patented Dec. 3|, 190|.

W. B'URL|NGHAM.-

Y PNEUMATIG HAMMER.

(Applimion med um. 2e, 1901.)

(No Modal.) 4 Sheets-:Sheet L liv .Mm .,i l. i

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No. 690,358. Y Patented Dec. 3|, l90l.

' W. BURLINGHAM.

PNEUMATIC HAMMER.

(Application led Mar. 26, 1901.)

4 Sheets-Sheet 2.

(No Modal.)

No. 690,358. Patentd Dec. 3|, |90l. W. BUBLINGHAM.

PNEUMATIC HAMMER.

(Application Bled-Mar. 26, 1901.)

(No Model.) 4 Sheets-Sheet 3.

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ze 2Q z 2z 19 S14/vmbo@ @57 MMM ND. 690,358. I Patented 'Dec.'3|, 190|.

- W. BURLINGHAM.

PNEUMATlc HAMMER.v

(Appliwtion med Mar. 2e, 1901.)

4 Sheets-Sheet 4.

(No Model.)

JIIlIn ma@ WM..

E NORRIS PETERS FNUTLLITNU.. WASHINGTON D C Strom UNITED STATES PATENT OFFICE. y

VILLIAM BURLINGHAM, OF RICHMOND, VIRGINIA, ASSIGNOR OF ONE- TI-IIRD TO WILLIAM R. TRIGG COMPANY, OF RICHMOND, VIRGINIA,

A CORPORATION OF VIRGINIA.

PNEUMATIC HAMMER.

SPECIFICATION forming part of Letters Patent No. 690,358, dated `December 31, 1901.

Application filed March 26, 1901. Serial No. 52,982 (No model.)

To @ZZ whom, t may concern:

Beit known that I, WILLIAMBURLINGHAM, a citizen ofthe United States,residin g at Rich` mond, in the county of Henrico, State of Virginia, have invented new and useful Improvements in Pneumatic Hammers, of which the following is a specification.

My invention relates to power-driven devices, more particularly of the pneumatic type commonly known as pneumatic hammers, and has forits objects certain im provements in the construction and arrangement of the parts as follows: first, to provide an improved construction and arrangement of the main valve thereof located between the cylinder and the breech-piece of the tool and cont-rolled in its movement and controlling the admission and escape of air behind the piston by a novel arrangement of parts and passages; secondly, to providea constant airpressure to force the main valve to its cut-oif and escape position with respect to the rear side of the piston, said communication being established through a novel arrangement of passages and ports controlled by the piston; thirdly, to provide a cut-off valve independent of the throttle-valve, adapted to be adjusted to partially or wholly close off the airsupply to the main valve and also adapted to be automatically closed, if desired, at any predetermined point in the forward movement of the piston to shut off the air-supply, and thus regulate to a nicety the force of the blow imparted bysaid piston, said closure being caused by the air-pressure and without permitting the escape of the air already admitted behind the piston to give its stroke; fourthly, to provide an improved means for locking the cylinder and its breech-piece together, and thus preventing their unscrewing under the constant vibration or jar, a defect heretofore found very annoying. These bjects and also certain other minor improvements I attain in the manner and by the means hereinafter described and claimed, reference being had tothe accompanying drawings, in which- Figure 1 is a central longitudinal sectional view of my improved device, the same being taken on the line 1 1, Fig. 6. Fig. 2 isa longitudinal sectional vie-w of one-half of the tool, taken on the line 2 2, Fig. G. Fig.' 3 is a similar View ot' the tool, taken on the lines 3 3, Figs. 7, 8, 9, and 12. Fig. 4t is a view similar to Fig. 3, showing the piston in a different position. Fig. 5' is a transverse section takeii on the line 5 5, Fig. l. Figs. 6 to 12, inclusive, are transverse sections taken on I.

the lines in Figs. l and 3 correspondingin numbers withthe numbers of said figures, respectively. view illustrating the cut-off valve and its operating mechanism. Fig. 14 is a sectional view taken on the line 14 14, Fig. 1. Fig. 15 is an enlarged detail end elevation of the main valve. Fig. 16 is an enlarged detail side elevation, partly in section, of said main valve and a portion of the cylinder. Fig. 17 is an enlarged detail end elevation, and Fig. 18 an enlarged detail side elevation, partly insection, of the cut-od valve. Fig. 19 is a side elevation of a modified construction, showing the handle in a different position. 20 is a central longitudinal sectional View illustrating a modified construction of piston. Figs. 2l and 22 are det-ail views illustrating modified constructions of the handle.

In the said drawings the reference-numeral 1 denotes the hollow handle of the tool, through which the fluid-pressure is supplied in the usual manner, the same being preferably formed integral with the breech-piece 2,

which is, in turn, in screw-threaded engage- 'ment with the cylinder' or barrel 3, as shown.

Leading from the hollow interior of the handle 1 into the breech-piece 2 is a passage 4, that communicates at its front end with a passage 5, which in turn communicates with an annular chamber 6. Also divergiug from passage 4 before it reaches passage 5 are two passages 7, that in turn communicate with passages 8, the latter communicating with longitudinal passages 9, extending along the cylinder or barrel 3 and opening thereintoat 10, as shown in dotted lines in Fig. l and in section in Figs. 2 and 6.

Adapted to be moved transversely across the passage 5 is a throttle-valve 11, the same being mounted on a stem 12, carrying at its rear end a finger-trigger 13, as shown. On

Fig. 13 is an enlarged detail sectional.

Fig.

the end of a smallerstem 14, projecting from the front end of throttle-valve 11, is an enlargement 15, over which is adapted to 'freely slide a cut-off valve 16, the same being clearly shown in detail in Figs. 17 and 18 and consisting of a hollow body portion adapted to reciprocate over the enlargement 15, and a head closing its outer or rear end. Tapped into the chamber containing this cut-olf valve 16 is a regulating-screw 17, by the manual adjustment of which the movement of the cut-off valve 16 away from the throttle-valve 11 may be controlled. Leading from the passage 4 is a passage 18 for supplying constant fluid-pressure to the rear side of throttle-valve 11, as will be readily understood.

Located between the cylinder or barrel 3 andl breech-piece 2 is an annular main valve 19, the same having its forward end slightly larger in diameter than its rear end, as shown in Fig. 16, and being provided with anannular internal recess 20, having ports 21, com niunicating with the exterior and. with a larger annular external recess 22, having ports 23, communicating with the interior. Suitable pins 24, seated in the ends of said valve 19 and moving in recesses 25 in the cyln inder 3 and breech-piece 2, are adapted` to act as dash-,pots to cushion the reciprocating strokes of said valve 19.

Near the rear end of the cylinder 3 is aseries o f short longitudinal passages 26, closed` at their rear ends by the breech-piece 2 and each having two ports 27 and 28 opening eX- ternally and a single port 29 opening internally. Passing through the breech-piece 2 and, communicating with the main valve chamber is a series of ports 30.

Referring more particularly7 to Figs. 3 and 4, it will be seen that there isa series of longitudinal passages 3l in the cylinder 3, extending f-roni about half-way of the main portion of said cylinder to the rear end thereof and closed by the breech-piece 2, said passages each having'two ports 32 and 33 therein, nearits frontend, communicating with the interior of the cylinder 3, and a single port 3 4, midway of its length, communicating with the front end of the annular main-valve chamber. Passing through the cylinder 3 to atmosphere is a series 0f ports `41, the saine 1ying in the saine transverse plane with ports 32, as more clearly seen in Fig. 5.

' Located in the cylinder 3 is the piston 35, the same having its front portion slightly smaller in diameter than its rear portion,

Msaid rear portion having near its front end an annular recess 36 and near itsrear end a similarannularrecess37. Runningcentrally and longitudinally through vsaid piston 35 is a passage38, the same terminating atits rear end at the annular recess 37, into which it opens through ports 39, and at its front end just in front of thelarger rear portion of the piston, where it opens into the cylinder-chamber through ports 40.

From the above description the general operation of the tool will be understood to be as follows: The piston 35 being in its rearmost position, as shown in Fig. 1, and fluidpressure, such as air, admitted to the hollow handle 1, when the throttle-Valve 1l is retracted by the fingers of the operator grasping the trigger 13 the air passes through passage 5 into the annular chamber 6, where by reason of its pressurek against the surface afforded by the shoulder formed by the slightlylarger front end of the main valve 19 said valve is forced forward to the position shown in Fig. 1, thus bringing ports 21 and 27 in register with said ann ular chamber 6 and permitting the free passage of the air into passages 26 and from thence through ports 29 into the rear end of cylinder 3, behind the piston 35. This pressureinstantly forces said piston forwardit-s full stroke to the position shown in Fig. 3. Itwillvbe observed that the passages 9 are at all times in free communication. with the air-pressure` in handle 1 vthrough passages 4, 7, and 8 and that through chamber and force said main valve 19 at once to its rearmost position. (Shown in Fig. 3.) This results in closing the air-passage from annular chamber 6 to passages 26, but opens a path of escape to atmosphere for the airbehind the piston 35 through ports 29, passages 26, ports 23 and 23, annular recess` 22, and ports 30. The pressure in thefront end of the main chamber of the cylinder 3 being constant, however, through passages 9 and ports 10, this pressure, acting on the shoulder formed by the slightly-larger rear portion of the piston 35, at once forces said piston back again to its rearmost position, (shown in Fig. 1,) and when in said position the annular recess 36 in said piston will register with the ports 32, leading from passages 31. Now when in this position said recess 36 also registers with the ports 41 in the cylinder 3, and a free escape to atmosphere for thev air in front of the main valve 19 is thus aorded through ports 34, passages 31, ports 32, annular recess 36, and ports 41. The vpressure thus being relieved from the front side of the main Valve 19, the latter is at once forced forward to its initial position (shown in Fig. 1) through the pressure of the air on the shoulder formed by the slightly-larger front end of said main valve, as heretofore described, thus again establishing communication between annular chamber 6 and the rear end of the TOO IIO

piston 35, and the tool is ready to repeat the operation heretofore described.

It will be observed that by reason of the constant air-pressure on the rear side of the throttle-valve 11 through passage 13 a release of the trigger 13 will instantly cause said throttle-valve'to be forced forward to close the passage 5, thus cutting olf the air-supply to the operating parts of the tool.

In order to provide for cutting off the airsupply to the piston 35 at any desired point intermediate its full stroke and without manipulating the trigger 13, I have provided a novel mechanism, as follows: Located longitudinally of the cylinder 3 is a passage 42, the same extending through the rear end of said cylinder and being provided with a plurality of ports 43, 44, and 45, opening into the cylinder-chamber, said passage 42 opening into a single passage 46, communicating with the rear side of the cut-off valve 16, as shown more clearly in Fig. 13. Situated in the passage 42 and adapted to be rotated therein is a hollow rod or stem 47, the same extending out through the breech-piece 2 and being provided on its outer end with a thumbpiece 4S for ready manipulation. Said rod or stem 47 is provided with a series of ports 49, 50, and 5l, corresponding in number to the ports 43, 44, and 45, and each adapted, when the rod or stem 47 is turned to the proper position, to register with its corresponding port 43, 44, or 45 in the cylinder 3. It will be observed, however, that said ports 49, 50, and 51 are so disposed around the rod or stem 47 that only one of said ports will register at a time with its corresponding port in the cylinder 3, and for convenience in manipulation the thumb-piece 48 is marked to indicate the position of these ports, as seen in Fig. 14, where the rod or stem 47 is shown turned to register the ports 43 and 49, as in Fig. 13. The operation of this feature of my invention will be understood from the above description to be as follows: With the rod or stem 47 in the position shown in Figs. 1 and 13, so that the ports 43 and 49 register, when the piston 35 makes its forward stroke the air-pressure will be maintained behind the same, as heretofore described, until its rear end passes port 43, so as to uncover the same, as seen in Fig. 13, when said pressure will instantly pass through ports 43 and 49, rod or stem 47, passage 46, and into the cut-owalve chamber in the rear of cut-oft' valve 16, where the pressure exerted thereon will at once force the same forward its full distance, thus completely closing the passage 5 and cutting off the air-supply to the piston 35, as clearly seen in Fig. 13, where the cut-off valve 16 is shown forced to its closed position across the passage 5. The expansive force of the air already in the vcylinder 3 behind the piston 35 will be sufficient to carry said piston to the end of its stroke, but with greatly-reduced force, when the main valve 19 will be shifted, as heretofore described, to permit the` escape of the air behind said piston and said cut-o valve 16 to atmosphere. The release of the pressure thus from the rear end of said cut-off valve will permit access of a small quantity of air between the front edge of said valve and the wall of passage 5,which will be sufficient to at once force said cut-o valve back to its initial open position, thus again admitting the air through passage 5 into annular chamber 6 for another stroke of the piston. It will of course be seen that if the rod or stem 47 be turned so that ports 44 and 50 register this cut-0E action will take place when the end of piston 35 reaches port 44, and also that if said rod or stem is turned to register ports 45 and 5l the cut-off action will take place when the end of the piston reaches port 45. This construction, therefore, aords aA means for accurately and automatically regulating the degree of power applied to the piston 35, as the trigger 13 requires no manipulation whatever, and when the rod or stem 47 is once turned to register certain ports each stroke thereafter will have exactly the same force. It will of course be understood that I do not limit myself to the number of adjustments shown for the rod or stem 47, as the same may be increased, if desired, so that closer graduations of power or an earlier cut-off may be obtained.

It will be observed that by means of theregulating-screw 17, tapped into the cut-off-valve chamber, the valve 16 may be forced forward permanently and independently of the airpressure to partially or even wholly cut off the passage 5. Thus with a constant air-pressure in the handle 1 and passage 4 the pressure admitted to the annular chamber 6 may be accurately adj usted independently of the throttie-valve 11 and without interfering in the least with the automatic action of the cut-off valve 16 through the rod or stem 47.

Heretofore in-devices of this character it has been found almost impossible to effectually lock the cylinder 3. and the breech-piece 2 together, even when screwed together as tightly as possible by power devices, for the constant jar due to the rapid reciprocation of the piston 35 inevitably tends to loosen said screw connection. To eectuallyobviate this, I have employed the following novel means: The cylinder 3 and breech-piece'2 are screwed together by power devices to the full limit and then unscrewed a fraction of an inch. A hole is then bored through the breech-piece 2 and part way into the cylinder 3, into which is forced a soft-metal plug 52. The parts are again screwed up to their limit,which slightly bends or upsets said plug 52 at the point ot' juncture of the cylinder and breech-piece, as seen in Fig. 11. This slight bending or upsetting of said plug 52 effectually prevents its withdrawal or working out, while at the same time the resistance offered by said plug to the unscrewing ofthe parts has been found in practice to be absolutely effectual. To separate the cylinder and breech-piece, it is only IOO IIO

necessary to apply power devices thereto to unscrew the same, when the plug 52 will he sheared oif at the point of juncture of said cylinder and breech-piece, and the two pieces thereof can be readily removed when the parts are separated. To reassemble the parts, the above operation is repeated with a new plug 52, except that no fresh hole has to be bored.

In Fig. 2O I have illustrated a slight modiication in which the same results are accomplished, although the piston 35 is shortened to about one-half its length. To accomplish this, the general operation of the parts is the same, except that the cylinder 3 has a slightlyenlarged chamber 53 for part of its length, and the air-pressure through passages 9 and ports 10 exerts its rearward pressure on a collar 54 at the rear end of the piston 35. When said piston reaches its forward. position, the air passes from chamber 53 through ports 55, then ce through a short interior passage in the piston to ports 56, corresponding to ports 39, thence into annular recess 37, and from thence into passages 3l through ports 33.

In Fig. 19 I have illustrateda modified coustruction of handle particularly well adapted for use in planishing and work of a like character, said handle 57 lying parallel with the body portion of the tool, so'that the latter may be held vertically over the surface to be operated on. f

In the use of these tools heretofore th shock due to the vibration has been found to be harmful to the workmen manipulating thesame, and this I aim to overcome by employing a handle 5S, attached to the body portion of the tool by a spring 59, the resiliency of the latter taking up said vibration. In this construction, of course, the air must be admitted to the body portion of the tool direct through the tube 60. Still another means of overcoming this objection is illustratedin Fig. 22, wherein the handle 6l is connected to the tool proper by means of a piston-head 62, havinglimited play in a cham-` ber 63, to both sides of which the air-pressure operatingthetoolis admitted, thus forming an effective air-cushion for minimizing the vibration or jar of the tool.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. In a pneumatic hammer, means for supplying-a constant air-pressure to the piston in a rearward direction, a main valve, means for supplying a constant air-pressure to a limited area of said valve in a forward direction, and means for automatically admitting the air-pressure on thefront side of the piston to the front side of said valve when the piston reaches its forwardlimit of movement to shift said valve to cut off the air-pressure on the rear side of the piston, substantially as set forth.

2. In a pneumatic hammer, means for sup- A plying a constant air-pressure to the piston in a rearward direction, a main Valve, and a chamber in said pistonin constant communication with said air-pressure, said chamber adapted to communicate with the front side of said main valve when said piston reaches its forward limit of movement to shift said valve to cut off the air-pressure on the rear side of the piston, substantially as set forth. 3. In a pneumatic hammer, a main'valve, and a piston having an annular recess therein intermediate its length and an annular recess near its rear end, said forward recess adapted to establish communication between the front side of said valve and the atmosphere when said piston is in its rearmost position, and said rear recess adapted to establish communication between the constant air-pressure and the front side of said valve when said piston is in its foremost position, substantially as set forth.

I 4. In a pneumatic hammer, a piston provided with an ann ularrecess intermediate its length, an annular recess near its rear end,

,and a central chamber opening in front of said forward recess and into said rear recess, means for supplying a constant air-pressure on said piston in a rearward direction, said pressure communicating freely with said chamber, and a main valve having communication from its front side with the cylinder, the whole cooperating so that when the piston reaches its forward limit of movement communication is automatically established through said rear annular recess and central chamber betweenA the constant air-pressure and the front side of said valve, and when said piston reaches its rear limit of movement communication is established through said forward annular recess between the front side of said valve andi the atmosphere, substantially as set forth.

adapted to reciprocate over a projection on the throttle-valve across the air-passage to the main valve of the hammer, and an adjustingscrew contacting with the rear side of said cut-off valve for adjusting the samepermanently to limit or cut olf the air-supply to the main valve, substantially as set forth.

7. In a pneumatic hammer,the combination with thel main valve, and the piston, of a cutoff valve adapted to be automatically operated at any predetermined point in the forward movement of the piston to cut olf the passage of the air to the main valve, substantially as set forth.

S. In a pneumatic ham mer,tl1e combination with the main valve, and the piston, of'a cutoff valve adapted tov be automatically oper- IIO ated by the air-pressu re at any predetermined point in the forward movement of the piston to cut off the passage of the air to the main valve, substantially as set forth.

9. In a pneumatic hammer,the combination with the main valve, and the piston, of a cutoff valve adapted to be automatically operated by the air-pressure at any predetermined point in the forward movement of the piston to cut off the passage of the air to the main valve and without permitting the escape of the air behind the piston, substantially as set forth.

10. In a pneumatic hammer, the combination with the main valve, and the piston, of a cut-o valve adapted to be automatically operated by the air-pressure at any predetermined point in the movement of the piston to cut 0E the passage of air thereto, and means for varying this point of cut-off, substantially as set forth.

ll. Ina pneumatic hammer, the combination with the main valve, and the piston, of a cut-off valve adapted to be automatically operated by the air-pressure at any predeter-` mined point in the forward movement of the piston to cut off the passage of the air to the main valve, and meansfor varying this point of cut-oif, substantially as set forth.

12. In a pneumatic hammer, the combination with the main valve, and the piston, of a cut-off valve adapted to be automatically operated by the air-pressureat any predetermined point in the forward movement of the piston to cut off the passage of the air to the main valve, and means for varying this point of cut-off consisting of a hollow rod or stem communicating with the rear side of'said cutoff valve and adapted by its rotation in its seat to establish communication with the cyl- 4o inder-chamber at any predetermined point to admit the air-pressure therefrom againstthe rear side of said cut-o valve as the forward movement of the piston uncovers said point of communication, substantially as set forth. 45 13. In a pneumatic hammer, the combination with the piston, and the cylinder having a vseries of ports therein of a cut-olf valve, and a hollow rotatable rod or stem, said rod or stem covering said ports and having a series 5o of similar ports therein, the same being disposed ,on different sides thereof and each adapted to register with one of the cylinderports when turned to the proper position, said rod or stem communicating with the rear side 5 5 of said cut-off valve to admit the cylinder airpressure thereto as the registered port-s are uncovered by the forward movement of the piston, substantially as set forth.l

. 14. The Combination with two parts, such 6ov as the cylinder and breech piece of a pneumatic hammer, screwed together, of a softmetal plug located in a hole common to both parts, said parts having been turned to bring the two parts of said hole slightly out of aline- 6 5 ment after the insertion of said plug, substantially as set forth.

In testimony whereof I have hereunto set my hand in the presence of two subscribing 

